(1) Field of the Invention
The present invention relates to the characterizing clauses of the independent claims. With these the invention generally deals with determining distances and/or positions.
(2) Description of Related Art
It is frequently necessary to be able to measure comparatively short distances in the range of several centimeters up to several hundred meters fast and very precise. Applications for this are for example measuring existing real estates, the measurement of properties, during the construction of houses, as well as measuring distances of mobile machinery, for example transport systems in industrial halls, whose distance from walls or such must be determined, in order to stop the movement if necessary before a collision occurs.
Beyond that it is often not only necessary to determine the distance for a point of reference but also to determine a relative position to this point of reference depending upon application in two or three dimensions, i.e. typically the position on an area or in addition also the height.
Now different methods are suggested, in order to deal with these measuring tasks.
Thus for example the U.S. Pat. No. 5,949,530 suggests a method, which emits a pulsed laser beam and determines the distance to a distant object from the running time of the backscattered pulse. Systems of this type are already used in industrial applications, they are however expensive, as the running times of the light pulses are short and a gating electronic operating at high frequency operating is required, which must respond accordingly quickly.
Further arrangements are well-known, in which signals are modulated on signal beams and a value related to the modulation, e.g. the phase, is used for the determination of the distance to the signal generator.
Apart from the described timing of the interval between transmission and echo-return and the phase measurement with suitable modulated laser light further methods are well-known like the active triangulation, with which e.g. backscattered laser light is detected with a position-sensitive detector (PSD), in order to conclude the distance to the object points from the position of a light spot imaged on this detector.
Further arrangements are well-known with which a light emitter is aligned accurately to the vertical lie, in order to then emit a light beam along a horizontal line or a system of coordinates as reference. Hereby measurements can be facilitated, however they cannot be taken easily.